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Legacy Modernization

Legacy application modernization, one system at a time

For teams running software that still works but has become expensive to change. We assess what you have, scope one system on a fixed price, and migrate it in slices while the existing version keeps serving traffic. No eighteen-month rewrite, and no launch night where everything changes at once.

Years of Industry Experience
10+
Global Clients
350+
Projects Delivered
420+
Tech Engineers
35+

When a system that works starts costing you

Legacy does not mean old. It means the cost of changing it has outgrown the value of keeping it as it is.

Every change takes weeks

A one-line business rule turns into a three-week release because nobody is certain what else it touches, and the person who wrote it left in 2019.

You are one dependency away from stuck

The framework version is past end of life. A security patch lands and there is no upgrade path that does not break something you cannot test.

The hosting bill outgrew the system

You are paying for an always-on server sized for a peak that happens twice a year, because the app cannot scale any other way.

The data is trapped

Reporting means exporting a CSV. Another tool needs the same records, so somebody keys them in twice, and now the two disagree.

The five approaches to legacy system modernization

Most real projects use more than one, applied to different parts of the same system. The assessment decides which goes where.

Rehost

Move it as it is

Lift the application onto managed cloud infrastructure without touching the code. Fastest and cheapest, and it fixes hosting problems only. If the code was the problem, rehosting moves the problem.

Right when: The app is fine, the server it lives on is not.

Replatform

Move it and update the runtime

Same application, but the language runtime, database, and dependencies come up to supported versions, usually with containers so the environment stops being a snowflake.

Right when: You are stuck on an end-of-life version and need supported ground.

Refactor

Restructure the code, keep the behaviour

The system keeps doing exactly what it does now, but the internals get pulled apart so a change in one place stops breaking three others. Tests go in first so we can prove behaviour did not move.

Right when: The business logic is right; the structure around it is not.

Rebuild

Rewrite a piece at a time

New implementation, same job. We do this behind a routing layer so old and new run together and traffic moves across gradually, rather than a launch night where everything changes at once.

Right when: The design cannot carry where the business is going.

Replace

Buy instead of build

Sometimes the honest answer is that an off-the-shelf product does this now, and the work is migration and integration rather than development. We will tell you when we think that is the case.

Right when: The system is no longer a differentiator for you.

What we modernize, and what we do not

A modernization partner who claims every platform is telling you something about their sales process, not their engineering.

We work on

  • Web applications on PHP, .NET, Java, Node, Python and Ruby
  • Front ends on jQuery, AngularJS and other end-of-life frameworks
  • Monoliths that need splitting into services, or services that should be merged back
  • On-premise and single-server apps moving to AWS, Azure or GCP
  • Database migrations, schema clean-up and reporting layers
  • Mobile apps on unsupported SDKs, including hybrid rewrites
  • API layers over systems that currently have none

We refer out

  • Mainframe and COBOL estates
  • AS/400 and iSeries migration
  • SAP ECC to S/4HANA programs
  • Embedded and industrial control firmware

These need platform specialists who do that work daily. If that is your estate, we will say so on the first call rather than three weeks into an engagement.

The jumps we make most often

Not an exhaustive list, and yours may combine several of these. If your stack is not here, ask anyway.

  • AngularJS / jQuery front endReact or Next.js, typed
  • .NET Framework on Windows ServerModern .NET, containerised
  • PHP 5 / 7 monolithSupported PHP or a rewritten service
  • Single VM or on-prem boxAWS, Azure or GCP managed services
  • Unversioned SQL Server or MySQLManaged Postgres or MySQL, migrated
  • One database shared by every appOwned schemas behind APIs
  • Cordova / unsupported native SDKReact Native or Flutter
  • Manual FTP or hand-run deploysGit-based CI/CD with rollback

How the work actually runs

The first deliverable is a document, not a commitment.

01

Assessment before anything is promised

We read the code, the deployment setup, and the database. You get a written map of what the system does, what is genuinely risky, and which of the five approaches fits each part of it. This stands on its own; if you take it to another firm, it still works.

02

A scoped plan with a fixed price

Not a multi-year program. One system, or one part of one, with a defined outcome and a number attached before work starts. If a phase does not justify itself, it does not go in the plan.

03

Strangle it, do not switch it

New code goes in behind a routing layer while the old system keeps serving traffic. Functionality moves across in slices you can verify, and every slice can be turned back. There is no launch night.

04

Handover you can actually use

Tests, deployment scripts, and documentation written for whoever maintains this next. The point is that you are not dependent on us afterwards.

The two ways these projects go wrong

The big-bang rewrite

The classic failure: a team rebuilds for eighteen months against a moving target, the old system keeps changing underneath, and the new one never catches up. Incremental migration behind a routing layer is slower on paper and far more likely to finish.

Undocumented behaviour

Old systems accumulate rules nobody wrote down, and some of them are load-bearing. We characterise existing behaviour with tests before changing it, so the question stops being what should this do and becomes what does this do today.

Data you cannot afford to lose

Migration is the moment records are most at risk, so it runs with the old system still holding the source of truth until the new one is reconciled and verified against it.

  • GDPR, and HIPAA or PCI DSS where they apply to your data
  • Access control and audit logging built in, not added later
  • Reversible cutovers, so a bad slice rolls back instead of forward
  • Row counts and checksums reconciled before the old system is retired

We build to these requirements. Where you need an audited certification held by the vendor, say so early and we will tell you honestly whether we clear that bar.

Industries we have modernized systems for

  • Healthcare
  • Fintech and payments
  • Logistics
  • Retail and e-commerce
  • Education
  • Real estate
  • Manufacturing
  • Professional services

Related services

Systems We've Shipped

Platforms and applications running in production for real businesses. Each card opens the full case study.

Legacy modernization questions

What teams ask before committing to a modernization project.

Updating software you already depend on so it is cheaper to run and safe to change, without losing what it does. In practice it is one of five approaches: rehosting it onto better infrastructure, replatforming it onto supported runtimes, refactoring its internals, rebuilding parts of it, or replacing it with a product. Most real projects use more than one, applied to different parts of the same system.

It depends on which approach the system needs, and that is what the assessment establishes. A rehost is a fraction of a rebuild. The honest answer is that anyone quoting a figure before reading your code is guessing. We scope it after the assessment and give you a fixed price in writing, so the number you approve is the number you pay.

That is the default approach. New functionality runs behind a routing layer alongside the existing system, and traffic moves across in slices rather than at a single cutover. Each slice can be reversed. Some database migrations need a short planned window, and we tell you which ones in the assessment rather than on the night.

No. Mainframe, AS/400 and COBOL estates need specialists in those platforms, and we are not them. We work on web, mobile, cloud and database systems. If your estate is mainframe, a firm that does that work every day will serve you better than we would.

Usually modernize. A rebuild throws away years of accumulated business rules, including the ones nobody documented, and those rules are often the actual product. A rebuild makes sense when the existing design genuinely cannot support where the business is going, and the assessment is what tells us which situation you are in.

The assessment is typically one to three weeks. After that it depends entirely on scope and approach, which is why we scope one system at a time rather than quoting a program. You see working software in stages throughout, not at the end.

Start with the assessment

Thirty minutes to talk through what you are running and what it is costing you. If modernization is not the right move yet, that is a fine outcome and we will say so.